Accessing the brain’s interstitial space for sampling and monitoring of small-molecular-weight constituents is only effective with the proper fluid-delivery tools in place. Microdialysis techniques depend on programmable syringe pump capable of steady and exact microflow volume rates for controlled support. At the method’s core is the semipermeable membrane-containing probe, through which, via constant perfusion, molecules from the extracellular space are collected.1 Membranes differ in their pore size and material, but flow through the membrane is based on the diffusion of molecules along their concentration gradient (i.e., Fick’s law), where those greater than 20,000 Da are generally limited.1,2
Microdialysis Monitoring: A Procedural Close-Up
In vivo microdialysis is perhaps most advantageous in its ability to sample extracellular fluid from the brain of a live animal, as opposed to analyzing post-mortem tissue. Moreover, the principle of “reverse or retro dialysis” allows for low-molecular-weight drugs to be delivered to predefined regions of the brain.2 ...
